Bumping gaia.json for 2 gaia-central revision(s)

========

https://hg.mozilla.org/integration/gaia-central/rev/c531ac4a3ebe
Author: Rudy Lu <left.lu@gmail.com>
Desc: Merge pull request #11548 from RudyLu/keyboard/Bug902352-placeholder_as_word_separator

Bug 902352 - Make Gaia keyboard treats the placeholder
r=timdream

========

https://hg.mozilla.org/integration/gaia-central/rev/8f7ba73087f4
Author: Rudy Lu <left.lu@gmail.com>
Desc: Bug 902352 - Make Gaia keyboard treats the placeholder
character U+FFFC as word separator.